Elongated spring coil conductors applying tension force to pushbutton actuators in keyboard matrix switch assembly

ABSTRACT

A matrix of conductors is secured within a housing in a normally separated relationship. One set of the conductors is comprised of a flexible material and is positioned in the housing relative to keyboard pushbuttons for providing tensioning force under the pushbuttons. When a pushbutton is depressed, a flexible tensioning conductor is depressed into contact with another conductor of the matrix for providing an electrical output representing the depressed pushbutton.

United States Patent i191 i111 3,743,798 Pentecost i [45] July 3, 1973 [54] ELONGATED SPRING COIL CONDUCTORS 2,320,774 6/1943 Plym 20o/5 EA APPLYING TENSION FORCE To 3,205,318 9/1965 Bilek 20o/5 E PUSHBUTTON ACTUATORS 1N KEYBGARD 3,193,607 7/l965 Anderson... 200/159 R X 3,396,257 8/1968 Vazquez 200/166 BA MATRIX SWITCH ASSEMBLY 3,362,004 M1968 Bang 20o/166 BA x ['75] Inventor: Eugene E Pentec0St,Anaheim 3,470,332 i 9/1969 M11ner.... 20o/5 EA X Call-f 2,025,981 12/1935 Getty 20G/159 B UX 3,432,635 3/1969 Soprani 200/166 BA 959,435 5 1910 200 166 A UX [731 Assignee: North American Rockwell Corporal Thomson l B non El Segundo Calif' Primary Examiner- James R. Scott [22] Filed: Selm 13, 1971 Attorney-L. Lee Humphries et al. [21] Appl. No.: 179,882

i [57] ABSTRACT v [52] U-S- Cl 200/5 R, 200/ 159 R, 200/ 166 BA A matrix of conductors is secured within a housing in [5 l] Int. Cl. H01h 13/28 a normally separated relationship. One set of the con- [581 Field 0f Search 200/5 R, 5 E, 5 EA, ductors is comprised of a flexible material and is posi- 20o/61.78, 159 R, 159 B, 166 BA, 5 A tioned in thehousing relative to keyboard pushbuttons for providing tensioning force under the pushbuttons. [56] References Cited When a pushbutton is depressed, a flexible tensioning UNITED STATES PATENTS conductor is depressed into contact with another con- 3 684 S42 8/1972 Boulanger 20o/159 B x duciof of the matrix foi providing a eiectiicai Output 316001528 811971 Leposavic 20o/159 B X representing the depressed Pusibuite 3,617,660 1l/1971 Krakinowski ZOO/159 B X 4 Claims, 2 Drawing Figures Patented July 3, 1973 3,743,798

FIG. 2

INVENTOR EUGENE E. PENTEcosT BY ATTORNEY ELONGATED SPRING COIL CONDUCTORS APPLYING TENSION FORCE TO PUSHBUTTON ACTUATORS IN KEYBOARD MATRIX SWITCH ASSEMBLY BACKGROUND OF THE INVENTION l. Field of the Invention The invention relates to a keyboard conductor matrix device and, more particularly, to such a device in which one set of the conductors comprising the matrix is utilized to spring tension pushbuttons of the keyboard as well as provide a signal representing a depressed pushbutton when two conductors of the matrix are formed into contact.

2. Description of Prior Art U.S. Pat. No. 2,931,877, issued Apr. 5, 1960 to E. J. Henley for Electrical Contact Device, describes the intersection of a flexible conductor and a deformable semiconductive member. The patent does not show a conductor matrix comprised of one set of flexible conductors disposed at right angles to a set of deformable semiconductor members secured within a housing in such a way that the flexible conductors provide tensioning for the pushbuttons of the keyboard. In addition, the patent does not teach structure necessary to properly house the pushbuttons, and the conductor ma trix as described herein.

SUMMARY OF THE INVENTION Briefly, the invention comprises a conductor matrix secured within a keyboard housing. The conductors are supported in a normally separated position. One set of the conductors is comprised of an elastic (flexible) conductive material, and the other set of conductors is comprised of a deformable conductive material in the v preferred embodiment.

The flexible conductors are secured within the housing subjacent the bottom surface of the pushbuttons of the keyboard such that an upward spring tensioning force is exerted against the pushbuttons. As a result, the pushbuttons are held in a proper position in the housing. lf moved position of a pushbutton is quickly restored by the spring tensioning force of the flexible member. In the preferred embodiment, the flexible member may be fabricated from a conducting metal in the form of a coiled spring for providing improved tensioning of the pushbuttons.

OBJECTS AND ADVANTAGES The pushbutton includes prongs which project downward about the intersection of the conductors. Slots are provided in the housing for the prongs to reduce pushbutton wobble and to insure that the undersurface of the pushbutton correctly forces one conductor into contact with'its subjacent conductor.

In the preferred embodiment, the subjacent conductor is fabricated from a deformable conductive material such as a conducting rubber so that improved electrical contact results when the two conductors are depressed into contact. In other embodiments, however, a nondeformable conductor may be used in lieu of the deformable conductor.

Therefore, it is an object of this invention to provide a keyboard conductor matrix device which is relatively compact and easy to fabricate.

It is still another object of this invention to provide a keyboard conductor matrix device in which the housing provides support for the conductors of the matrix.

A still further object of this invention is to provide a keyboard device in which one set of the conductors is fabricated of a flexible material and is positioned in a housing to provide a spring tensioning force to maintain the pushbuttons of the keyboard in a correct posi tion.

A still further object of this invention is to provide an improved keyboard conductor matrix device in which one set of conductors of the matrix is comprised of a coiled spring for providing an upward force to hold the keyboard in the correct position in the keyboard housing and the other set of conductors is comprised of a deformable conductive material such that an improved electrical contact results when two conductors of the matrix are pressed into contact by a pushbutton.

A still further object of this invention is to provide an improved keyboard conductor matrix device in which pushbuttons are provided with downwardly projecting prongs to provide improved stability of the pushbuttons in the keyboard housing.

These and other objects of the invention will become more apparent when considered in connection with the description of the drawings, a brief description of which follows.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a perspective view, partially cut away, of a housing for the keyboard conductor matrix and keyboard pushbuttons.

FIG. 2 is a cross-sectional view of one corner of a keyboard housing showing enclosure of intersecting conductors by prongs of a pushbutton.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. l is a perspective view of keyboard housing l in which a flexible set of conductors 2 and a deformable set of conductors 3 are secured in a matrix (X-Y) arrangement. The housing, which may be comprised of a plastic material, is divided into an upper section 4 and a lower section S. Circular grooves, identified generally by numerals 6 and 7, are provided in the side of the upper and lower sections for engaging the ends of the set of deformable conductors identified by the numeral 3. A similar set of grooves is provided in the opposite side of the upper and lower members for securing the other end of the set of conductors identified by the numeral 3. In addition, grooves identified by the numerals 8 and 9 are provided in the orthogonal side of the upper and lower members for securing the ends of the set of flexible conductors identified generally by the numeral 2. Similarly, grooves are provided in the opposite side of the upper and lower members for securing the other ends of the set of conductors identified by the numeral 2.

Although more clearly shown in FIG. 2, the lower member 5 is provided with parallel grooves into which the set of conductors 3 are placed. The grooves are identified in FIG. 2 by the numeral l0.

The base member is also provided with regularly spaced ridges identified generally by the numeral 1l between each row of pushbuttons identified by numeral 12. The ridges ll include grooves 13 for supporting the conductors 2 between the sides of the upper and lower members.

The pushbuttons l2 include an upper portion ld which extends outward from the face l5 of the housing l. In addition, each of the pushbuttons is provided with an extended ledge 16 which is relatively larger than the opening 23 in the upper surface 15 such that the push buttons are retained inside the housing. In addition, each pushbutton is provided with prongs ll and if) which project downward from the bottom surface of the pushbuttons into mating openings identified generally by numeral 19 in the bottom surface 20 of the lower member 5. The prongs and the mating openings are utilized to prevent the pushbuttons from wobbling during an operation in which a button is depressed. It is also pointed out that the prongs project downward across the intersection of the conductor sets 2 and 3. As a result, a firm contact between the conductors is insured whenever a pushbutton is depressed. The openings 19 to the bottom surface 20 of lower member 5 can be seen more clearly in FIG. 2. The relationship of the prongs 17 and 13 relative to the intersecting conductors can also be seen more clearly.

The set of conductors 2 and 3 intersect substantially at right angles in the usual application. Conductor set 2 in the preferred embodiment is comprised of a coiled spring, fabricated of electrically conducting material which is secured within the housing l along the sides as shown, in such a way that the upper surface of the coiled conductors provides an upward spring tensioning force to the bottom surface of each of the pushbuttons. As a result, the pushbuttons are forced upward such that the ledges lo of the pushbutton are secured against the undersurface of the top layer H5. When a pushbutton is depressed, the operator forces the coiled spring conductor 2 into contact with the subjacent conductor of set 3. When the pushbutton is released, the spring tension provided by the coiled conductor forces the pushbutton back to its original position in the lnousn mg.

While the pushbutton is depressed for making electrical contact between the intersecting conductors, an electrical signal may be provided at the output of the pertinent one of the deformable conductors of set 3l. In other words, a voltage may be continuously provided by means of an electrical contact at the ends of the conductors of set 2. When one of the conductors is pressed into electrical contact with a conductor of set 3, a current path is provided so that a signal can be generated at the output of one of the conductors of set 3. Electrical contacts for the conductors are shown in schematic form and are identified generally by numerals 2li and 22.

The conductors of set 3 have been described as being deformable for improving the electrical contact be tween the sets of conductors when the pushbutton is depressed. In addition, the conductors of set 2 have been described as shown and a coiled set of conductors for providing spring tensioning to the pushbuttons of the keyboard as well as providing the required electrical circuit for generating an output signal representing the depressed key. It should be understood that other types of conductors could be used to implement the conductors of sets 2 and 3. It is necessary that the con ductors of set 2 be relatively flexible or elastic such that complete a particular and complete embodiment. For example, drive circuits, sensing circuits, display elements, etc. might be housed in a calculator case. The upper part of the housing (section 4) could be molded as part of the case. A substantial savings in cost would result.

In one embodiment, the housing l, including pushbuttons, may be comprised of a plastic material that can be formed in the configuration shown by molding,

land/or extruding techniques known to persons skilled in the art. The various slots, grooves, openings, etc. ca n be similarly formed simultaneously or edging or grinding techniques can be utilized in the formation. Such techniques and variations are believed known to persons skilled in the art. For that reason, the processes are not described in detail I claim:

ll. A keyboard device comprising a matrix of conductors;

a housing in which all of said conductors are secured in a normally spaced relationship; pushbuttons projecting from a surface of said housing for forcing said conductors of said matrix into temporary electrical contact; 9

said housing including a lower housing member subjacent the surface from which said pushbuttons project; l

a first set of said conductors comprising flexible conductors secured in said houshing for applying a spring tensioning force to said pushbuttons whereby said pushbuttons are maintained in a desired position in said housing;

said first set of conductors comprising a plurality of coiled spring conductors secured at opposite sides of said housing such that one surface of said coiled spring conductors provides said spring tensioning force to the undersurface of said pushbuttons; and a second set of said conductors being disposed in grooves in the inner surface of said lower housing member,

said second set of conductors comprising a plurality of conductors formed of deformable conducting material. 2. The keyboard device recited in claim 1 wherein said housing further includes regularly spaced ridges for providing additional support to said first set of conductors.

3. The keyboard device recited in claim l wherein each of said pushbuttons include prongs which project downward across the intersections of said matrix of conductors, and wherein said housing includes a lower surface provided with openings into which said prongs project for improving the stability of said pushbuttons in said housing.

d. A keyboard device comprising an array of electrical conductors including a first set of conductors arranged parallel to each other in a first plane and a second set of conductors arranged parallel to each other and transverse to said first set of conductors in a second plane; said tirst set of conductors comprising flexible conductors; y

said second set of conductors being supported throughout substantially the entire length thereof to prevent movement thereof;

control means normally supported in a first position by said flexible conductors and responsive to extersupport means for supporting said flexible conductors on both sides of the point of contact with said transversely disposed conductor in order to permit only one point of contact between said transversely disposed conductors.

gg@ TINTTEE STATES PATENT OFFICE @E'TMCATE 0F CORRECTION Patent No. 3,716,798 l Dated July 3, 1973 Inventong) Eugene E. Pentecost It is Certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as show-n below:

Column l, line 13, che "formed" to -foreed,.

Column la, line 2l, delete "9",

line 29, change "houshing" to housing-w Signed and sealed this 20th day of Novemberl 1973.

(SEAL) Attest z EDWARD M.FLETCER, JR REN A:D TEGTMEYER Attesting Officer' 1 Acting Commissioner of Patents *Zgjgo UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,'{1L3,798 r Dated July 3J! 1973 Inventor) Eugene E. Pentecost It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column l, line 13, change "formed" to -forced,.

Column la, line 21+, deleite "9",

Signed and sealed this V20th day of November 1973 (SEAL) Attest 3 EDWARD IJLFLETCHER, JR RENE D .TEGTMEYER Attesting Officer Acting,` Commissioner of Patents 

1. A keyboard device comprising a matrix of conductors; a housing in which all of said conductors are secured in a normally spaced relationship; pushbuttons projecting fRom a surface of said housing for forcing said conductors of said matrix into temporary electrical contact; 9 said housing including a lower housing member subjacent the surface from which said pushbuttons project; a first set of said conductors comprising flexible conductors secured in said houshing for applying a spring tensioning force to said pushbuttons whereby said pushbuttons are maintained in a desired position in said housing; said first set of conductors comprising a plurality of coiled spring conductors secured at opposite sides of said housing such that one surface of said coiled spring conductors provides said spring tensioning force to the undersurface of said pushbuttons; and a second set of said conductors being disposed in grooves in the inner surface of said lower housing member, said second set of conductors comprising a plurality of conductors formed of deformable conducting material.
 2. The keyboard device recited in claim 1 wherein said housing further includes regularly spaced ridges for providing additional support to said first set of conductors.
 3. The keyboard device recited in claim 1 wherein each of said pushbuttons include prongs which project downward across the intersections of said matrix of conductors, and wherein said housing includes a lower surface provided with openings into which said prongs project for improving the stability of said pushbuttons in said housing.
 4. A keyboard device comprising an array of electrical conductors including a first set of conductors arranged parallel to each other in a first plane and a second set of conductors arranged parallel to each other and transverse to said first set of conductors in a second plane; said first set of conductors comprising flexible conductors; said second set of conductors being supported throughout substantially the entire length thereof to prevent movement thereof; control means normally supported in a first position by said flexible conductors and responsive to external force to be selectively movable to a second position to force said one of said flexible conductors into temporary contact with a transversely disposed conductor whereupon said flexible conductor tends to return said control means to said first position after removal of said external force; and support means for supporting said flexible conductors on both sides of the point of contact with said transversely disposed conductor in order to permit only one point of contact between said transversely disposed conductors. 